February 26-28, 2019

Colorado Convention Center
Denver, CO

Todd WiedemeierOwnerT.H. Wiedemeier & Associates, Inc.

Todd Wiedemeier has over 27 years of experience in the field of Environmental Engineering including experience in project management and technical direction. Prior to starting his own company, he was a Technical Director at Parsons. Mr. Wiedemeier's areas of expertise lie in evaluating natural attenuation and implementing bioremediation. Mr. Wiedemeier has conducted MNA evaluations and remediation feasibility studies, and/or installed and evaluated remediation systems at hundreds of sites contaminated with organic and inorganic compounds. Mr. Wiedemeier has published more than 150 technical papers, books, and training manuals on remediation topics since 1990.

BioPIC – A Spreadsheet-Based Decision Tool for Deducing Degradation Pathways and Selecting the Most Efficacious Bioremediation Approach for Chlorinated Ethylenes

Background/Objectives. Bioremediation, both natural and engineered, has emerged as the preferred remediation approach at many sites contaminated with chlorinated solvents. A number of prognostic and diagnostic tools are available, yet guidance documents to assist site owners in selecting the most efficacious remedy are limited. This presentation discusses an Excel®-based tool, BioPIC, that guides the user through selection of the most efficacious bioremediation approach at sites contaminated with chlorinated ethylenes. Further, if monitored natural attenuation (MNA) is the selected remedial approach, BioPIC allows the user to deduce the most important degradation pathway(s).

Approach/Activities. Protocols have existed for the evaluation and implementation of MNA and biostimulation for years, yet prior to this work, there was no clear guidance on how to choose between MNA, biostimulation, and bioaugmentation; a shortcoming that caused unnecessary expenses and potentially detrimental environmental impacts. In addition, the protocols that existed prior to this work were dated and did not consider the state-of-the-art prognostic and diagnostic tools that are available today. A systematic framework that effectively aids site owners in selecting the best bioremediation approach was developed under a project sponsored by ESTCP. This framework represents an extension of the 1998 USEPA Technical Protocol for Evaluating the Natural Attenuation of Chlorinated Solvents and, among other things, (i) incorporates quantitative information of Dehalococcoides mccartyi biomarker genes, (ii) uses compound-specific isotope analyses (CSIA), (iii) considers the contribution of abiotic transformation of contaminants, and (iv) recognizes that MNA is an important component of integrated remediation strategies. Based on this framework, an Excel®-based tool, BioPIC, was developed to guide users through a decision tree to determine the most efficacious action to meet site-specific remediation goals. The new framework takes into consideration a site’s biogeochemical profile in addition to site management requirements such as time constraints for regulatory compliance, cost, and risk tolerance. If bioremediation is required, BioPIC allows the user to determine if biostimulation alone is sufficient to effect site remediation, or if biostimulation in conjunction with bioaugmentation is required. If instead, it appears that MNA is the preferred remedial alternative, then BioPIC aids the user in determining site-specific degradation pathways. Successful selection and implementation of MNA often requires evidence of degradation and specification of degradation pathways.

Results/Lessons learned. BioPIC is a user-friendly Excel® tool based on the new ESTCP framework that integrates groundwater geochemical and contaminant data with quantitative real-time PCR (qPCR) and CSIA information, along with the current understanding of biological and abiotic degradation mechanisms. The integrated approach presented in BioPIC is a robust tool useful to identify the relevant degradation mechanism(s) at a site and to guide users in determining whether MNA, biostimulation, or bioaugmentation combined with biostimulation is the efficacious remedial approach to meet specific cleanup goals.